What Does B1477 Mean?
This code indicates the Body Control Module (BCM) has detected an abnormal short-to-ground condition in the wiper motor's high/low speed control circuit. The BCM monitors the current flow through the wiper motor circuit and has identified that voltage is being shorted directly to chassis ground instead of flowing through the motor properly. This prevents normal wiper operation at high and/or low speeds.
Common Causes
40%
Damaged wiper motor internal windings or brushes causing internal short to ground
30%
Chafed or damaged wiring harness between BCM and wiper motor with exposed conductors touching ground
20%
Corroded or water-damaged wiper motor connector causing short circuit path to ground
10%
Failed BCM wiper control relay or internal BCM circuit short
Diagnostic Steps
1
Step 1: Perform visual inspection of wiper motor connector for water intrusion, corrosion, bent pins, or melted terminals. Disconnect wiper motor connector and inspect both harness and motor sides for damage.
2
Step 2: Using a digital multimeter, measure resistance between the wiper motor hi/low speed circuit terminal (at disconnected motor connector harness side) and chassis ground. Reading should be infinite resistance (open circuit); any continuity indicates a harness short to ground.
3
Step 3: If harness tests good, measure resistance at the wiper motor connector terminals (motor side) between hi/low speed circuit and motor housing ground. Normal reading is typically 2-8 ohms; readings near 0 ohms or intermittent shorts indicate internal motor failure.
4
Step 4: Inspect entire wiper motor harness routing for pinch points, chafing against sharp edges, or areas where harness passes through body panels. Pay special attention to firewall grommets and cowl areas where water and mechanical stress are common.
5
Step 5: If all wiring and motor test acceptable, verify BCM connector terminals are clean and tight, then test BCM output circuit operation with a test light or scope to confirm BCM is not creating the short internally. Replace BCM if it produces shorted output.
6
Step 6: After repairs, clear codes, operate wipers through all speed ranges (intermittent, low, high) and verify code does not return. Monitor live data for proper current draw during operation.
Estimated Repair Cost
$150 - $650
Parts + labor, varies by vehicle and location
This code indicates the Body Control Module (BCM) has detected an abnormal short-to-ground condition in the wiper motor's high/low speed control circuit. The BCM monitors the current flow through the wiper motor circuit and has identified that voltage is being shorted directly to chassis ground inst...
The most common cause of B1477 (Wiper Hi/Low Circuit Motor Short To Ground) is: Damaged wiper motor internal windings or brushes causing internal short to ground
Typical repair costs for B1477 range from $150 to $650, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Vehicle is drivable but wipers may be inoperative or function erratically, creating significant safety risk during rain or snow conditions. Repair should be completed before operating vehicle in adverse weather to maintain adequate visibility.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B1477 to identify the root cause.
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Quick Info
Category
Body
System
Wiper/Washer System (Body Electrical)
Difficulty
Type
Manufacturer
Recommended Tools
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